The Pentagon is considering options to plug a potential gap in missile-warning satellite coverage that include using hardware developed for civil space programs , according to a senior U.S. Air Force official.

Gary Payton, deputy undersecretary of the Air Force for space programs, said the service is weighing the possibility of using infrared sensors and other NASA hardware, much of it flight-proven, to soften the potential impact of problems with the Space Based Infrared System (SBIRS) High missile warning system. The Air Force is considering reducing its purchase of SBIRS satellites, or possibly even terminating the program altogether, due to massive cost overruns and delays. Lockheed Martin Space Systems of Sunnyvale, Calif., is the SBIRS prime contractor.

The SBIRS problems have raised concerns about a gap in missile-warning coverage when the current Defense Support Program system begins to degrade. In a Dec. 1 interview, Payton said if the SBIRS purchase is curtailed, the NASA designed hardware could help provide a bridge in capability to any follow-on system.

NASA is viewed as one source of components because of the agency’s increased use of infrared sensors for astronomy missions like the Spitzer Space Telescope, which was launched in 2003, and the James Webb Space Telescope, expected to be launched around 2013, Payton said.

“The astronomy world is moving to infrared, and that brings with it very, very sensitive detectors, cryocoolers, [and] better optics,” said Payton, a former astronaut and deputy NASA administrator. “So at the component level, there are a lot of things that we’re looking at that could help us for missile warning and missile defense.”

Kenneth Krieg, undersecretary of defense for acquisition, technology and logistics, is expected to make a final decision on whether to curtail the purchase of SBIRS High spacecraft — or proceed on the current path to buy at least five dedicated SBIRS satellites — Dec. 13, Payton said.

The Pentagon review of SBIRS was mandated by a law known as the Nunn-McCurdy provision, which requires the military to recertify programs whose costs rise by 25 percent or more based on their importance to national security, evidence that the problems that led to the cost growth are under control and the lack of viable alternatives.

SBIRS High underwent this type of Nunn-McCurdy review in 2002, but the Pentagon chose to continue the program with more high-level oversight. The program also breeched the Nunn-McCurdy cost threshold of 15 percent in 2004, but cost growth of that level requires notification to Congress but not recertification of the program.

Lockheed Martin’s SBIRS contract includes four satellites to be placed in geosynchronous orbit, one spare spacecraft, two sensors to be hosted by classified satellites in highly elliptical orbits, and ground equipment.

Lockheed Martin has delivered the sensors for the elliptical-orbit satellites, and announced in late November that it was ready to begin thermal vacuum testing on the first infrared payload for the geosynchronous-orbit satellites.

When the SBIRS contract was awarded in 1998, it had a value of about $2 billion and the satellites were to begin launching in 2002. By the end of 2004, however, the price tag had ballooned to almost $10 billion, and the launch of the first dedicated satellite had been pushed out to no earlier than 2008. The launch dates of the elliptical-orbit satellites are classified.

In a press briefing at the Pentagon in March 2005, then-acting Air Force Secretary Peter B. Teets said that the service needed to begin replacing the Defense Support Program constellation by 2015 at the latest or it would risk a gap in missile-warning coverage.

Payton noted that the Air Force still has one Defense Support Program satellite left to launch. That satellite currently is expected to launch in early 2006.

Any gap-filler system likely would be less expensive than SBIRS but would not match what is planned for SBIRS in terms of capability, Payton said.

Whether or not the Pentagon will scale back its SBIRS purchase depends on its level of confidence that the program’s problems are behind it, Payton said. “If it’s an unknown cost and unknown schedule, and we don’t have confidence in either one of those, we have a duty to stop it,” he said.

Chip Manor, a Lockheed Martin spokesman, said that the company’s recent work on the SBIRS program should give the Pentagon confidence in the cost and schedule projections.

“We’re continuing to make significant progress, we’re meeting milestones, and we’re committed to successful execution on the program,” Manor said.

Erica Hupp, a NASA spokeswoman, did not return a phone call requesting comment about NASA’s potential role in helping to fill a possible missile warning gap.